I'm pretty disappointed with amount of details lost when denoise profiled is used.

Processed image looks as if it was pasteurized and blurred.

Image is taken with Sony a6000, Darktable's built-in denoise profile for ISO1600 is used with default settings. Initially I thought there's a problem with built-in profiles so I created a new set with "tools/noise/gen-profile" but saw no difference in processed result.

Attached is my original RAW file, meta-data from Darktable and RawTherapee, crops of the most problematic area from the image processed with RawTherapee and Darktable and screenshot with 2 output images side-by-side.

Probably I'm doing something wrong in DT and is too naive to expect default settings of denoise profiled module to produce acceptable results. But IMHO defaults should be usable while what I got printed 40x60 cm looks not that good.

Well I missed that part about blending... it was not obvious really.Is there a reason blending with corresponding mode is not selected by default?

Ok now I enabled blending uniformly with lightness (in "non-local means" mode) and I may barely see any effect of denoising, see attached screen-shots.

But in any case, loss of detail is kinda expected when denoising...

Indeed, but if you take a look at lest at comparison.png attached to initial report I hope you'll see how image clarity degraded.Well with my above comment we're moving to another... opposite discussion - properly blended denoising (here I mean "non-local means" mode only) makes no difference. What do I do wrong now?

But "wavelets" mode if blended with "color" really does something magical, see another screenshot.

Well I missed that part about blending... it was not obvious really.Is there a reason blending with corresponding mode is not selected by default?

Lack of code :)

Ok now I enabled blending uniformly with lightness (in "non-local means" mode) and I may barely see any effect of denoising, see attached screen-shots.

You may also want to try the HSV versions of those blend modes. (and maybe blend opacity)And, obviously you want to play with various settings of the module, i.e. patch size and strength.

But in any case, loss of detail is kinda expected when denoising...

Indeed, but if you take a look at lest at comparison.png attached to initial report I hope you'll see how image clarity degraded.Well with my above comment we're moving to another... opposite discussion - properly blended denoising (here I mean "non-local means" mode only) makes no difference. What do I do wrong now?

But "wavelets" mode if blended with "color" really does something magical, see another screenshot.

Or you can use equalizer and try to manually come up with settings to remove noise, the result may be better.

Well I missed that part about blending... it was not obvious really.Is there a reason blending with corresponding mode is not selected by default?

Lack of code :)

Ok that makes perfect sense :)

Ok now I enabled blending uniformly with lightness (in "non-local means" mode) and I may barely see any effect of denoising, see attached screen-shots.

You may also want to try the HSV versions of those blend modes. (and maybe blend opacity)And, obviously you want to play with various settings of the module, i.e. patch size and strength.

Sure, there're so many knobs and levers...

But in any case, loss of detail is kinda expected when denoising...

Indeed, but if you take a look at lest at comparison.png attached to initial report I hope you'll see how image clarity degraded.Well with my above comment we're moving to another... opposite discussion - properly blended denoising (here I mean "non-local means" mode only) makes no difference. What do I do wrong now?

But "wavelets" mode if blended with "color" really does something magical, see another screenshot.

Or you can use equalizer and try to manually come up with settings to remove noise, the result may be better.

Well if we're talking about one particular photo it may worth tinkering with lots of settings to make it as perfect as possible.

But being a hobby photographer I want to have some base-line that works good enough for most of pictures I want to keep (essentially obvious technical trash never passes selection stage). Basically I want something close to what people used to call "out of the camera" with one important difference: I don't care much about camera settings during real shooting. My camera just captures photons so the only settings I do care are exposure and aperture. Everything else like settings WB, adding contrast or moving to B&W I do at home in a raw converter. And so I'd like to focus on mentioned items: fixing WB if automatic WB failed; changing saturation; cropping & rotating etc while leaving denoise magic to the tool I use.

Anyways thanks a lot for pointing me to the manual.

Still maybe it worth either changing this issue or filing a new one to track requirement to add some "missing" code that enables blending with either "color" or "lightness" by default in "denoise profiled" module? IMHO it may help a a lot to newcomers like me.

I've been playing quite a bit with denoising tools over christmas and am now using a mix of denoised profiled (wavelets) blended with color and the equalizer to denoise my pictures. This works quite well (see attached DSC08042-darktable.jpg). I think it nearly reaches the default denoising of capture-one (also attached).

But why has denoising to be so tricky in darktable? Is there a lack of a good algorithm that could be implemented or is it a time constraint from developer side? I'm trying to understand because I would be interested in helping with that.